In printing devices as represented by printers, a printing process is generally carried out upon receipt of a print command and print data from a host device which is realized by an information processing device as represented by a personal computer or information portable terminal, etc., and in a printing process one often needs to carry out printing again using the same print data, as necessitated by undesirable print conditions and a shortage of print copies.
However, in a conventional printing device, once a printing process is run, the print data temporarily stored in a buffer (work memory) of the printing device are lost, and re-printing would require re-transmission of the same print data from the host device to be received again by the printing device for another printing process, requiring the user to operate the host device for re-transmission, and requiring the printing device to develop the print data again into the image data, and as a result operability and working efficiency suffer greatly and more burden is put on the host device.
In view of these drawbacks, for the purpose of omitting re-transmission of print data from the host device when re-printing the once printed print data, Japanese Unexamined Patent Publication No. 55783/1994 (Tokukaihei 6-55783) (published date: Mar. 1, 1994) (“prior art {circle around (1)}” hereinafter) proposes a printing device in which the print data sent from the host device are stored in a buffer, and by the provision of mode selecting means by which a normal mode and a re-use mode can be selected, the print data stored in the buffer are maintained when the re-use mode is selected.
However, in the technique as recited in prior art {circle around (1)}, it is required to install a large capacity buffer with enough free memory space to temporarily store various print data, and for this reason a low-end printing device, which is not opt for an expensive large capacity buffer is forced to adopt the same mode of re-transmitting print data from the host device as with the conventional method.
As another alternative, Japanese Unexamined Patent Publication No. 44529/1998 (Tokukaihei 10-44529) (published date: Feb. 17, 1998) (“prior art {circle around (1)}” hereinafter) proposes a printing method and printing device which take into consideration relatively cheaper printing devices with a small memory capacity, in which the time taken for a printing process is reduced by re-using the stored print data when the print data are within the capacity of the memory means, and when the print data exceed the memory capacity, only the print data re-transmitted from the host device are printed out so as to reduce the burden put on the host device.
Meanwhile, from a viewpoint of efficient use of resources and efficient use of space for a document, there is demand in printing devices which are capable of double-sided printing. However, double-sided printing cannot be carried out in the event where the buffer overflows while processing the print data of one side of the double-sided document in the printing device, and when that happens, they cannot be paired with the print data of the other side of the double-sided document.
In view of this drawback, Japanese Unexamined Patent Publication No. 207401/1996 (Tokukaihei 8-207401) (published date: Aug. 13, 1996) (“prior art {circle around (3)}” hereinafter) proposes a double-sided printing device, double-sided printing method, and double-sided printing system, in which a front page which was received first is stored so that it can be matched with the back page in output, and the front page is printed after printing the back page so as to prevent overflow without unnecessarily increasing the buffer capacity of the printing device capable of double-sided printing.
Further, Japanese Unexamined Patent Publication No. 190302/1997 (Tokukaihei 9-190302) (published date: Jul. 22, 1997) (“prior art {circle around (4)}” hereinafter) discloses a printing system which realizes double-sided printing with high throughput without unnecessarily increasing the buffer capacity by the provision of a page order rearranging control section in the host device, by which, to carry out double-sided printing, the order of pages to be transmitted to the printing device is rearranged in the order of double-sided printing.
However, in prior art {circle around (2)}, because the data to be used for printing of multiple copies are either stored print data or print data which were re-transmitted from the host device, the data are not used efficiently when the buffer overflows, and in this respect, prior art {circle around (2)} is not sufficient.
Further, the drawback of the techniques as recited in prior art {circle around (3)}and prior art {circle around (4)} is that they are insufficient when the capacity of the memory means is overflown by the print data when printing the first and last pages on a single sheet of paper as in brochure printing.
Further, in order for the host device to arrange the page order, means for carrying out such a function needs to be provided in the host device. However, in the case where non-page independent PDL (Page-Description Language) is used, the content of a succeeding page may have an adverse effect on the following page in a print job, which often makes it difficult to arrange the page order on the host side. Note that, the PDL refers to a printer control code (language) for creating a page image in page printing.